A conventional communication system enables a user to access a service-providing apparatus through operations on an image-forming apparatus so that, via the image-forming apparatus, the user can access services provided by the service-providing apparatus. Such services may include: downloading data stored on the service-providing apparatus and printing the data on the image-forming apparatus; uploading data scanned by the image-forming apparatus to the service-providing apparatus; converting the format of data uploaded to the service-providing apparatus on the service-providing apparatus; and uploading data collected by the image-forming apparatus to the service-providing apparatus.
In a conventional system, a user registers an image-forming apparatus on a service-providing apparatus using a personal computer, at which time the service-providing apparatus issues authentication information to the personal computer. By inputting this authentication information into the image-forming apparatus, the user can access services on the service-providing apparatus through the image-forming apparatus.